not about cannabis, smoking or schizophrenia. Rather it is about an artificial compound that is not present in cannabis, which was injected into rats, and which led to changes in their brain waves.

The article was debunked at the time, including by Neurobonkers and Clear. In the latter, it says:

Dr Matt Jones, lead author of the study in question...told me that he was “disappointed but not surprised” at the Daily Mail’s coverage of his work. He gave me permission to quote him in saying that “This study does NOT say that one spliff will bring on schizophrenia”.